The cost of colorectal cancer screening could be cut substantially without impairing its effectiveness by adopting a “resect and discard” approach for the smallest polyps, Dr. Cesare Hassan and his colleagues said.
A major portion of the cost of colorectal cancer screening is attributed to pathologic examination of polyps that are identified and resected. Among patients at average risk, more than 60% of all polyps detected at screening are diminutive (5 mm or smaller) and have an extremely low likelihood of being cancerous, said Dr. Hassan of Nuovo Regina Margherita Hospital, Rome, and his associates (Clin. Gastroenterol. Hepatol. 2010;8:865-9).
The “resect and discard” approach calls for simply discarding diminutive lesions rather than performing pathology exams on them. This approach is facilitated by the use of new colonoscopy technology that incorporates narrow-band imaging, which allows for better characterization of the smallest polyps and could conceivably avert further histologic assessment.
The investigators used mathematical modeling to create a cost-effectiveness simulation that would assess the potential savings of adopting a “resect and discard” approach for diminutive polyps in a hypothetical cohort of 100,000 average-risk American men and women aged 50-100 years. The hypothetical costs were calculated by using Medicare reimbursement data.
The model assumed that 85% of colorectal cancers develop from a polypoid precursor, and the remaining 15% are de novo tumors. It incorporated several possible health states: no colorectal neoplasia; diminutive (5 mm or smaller), small (6-9 mm), or large (10 mm or larger) adenomatous polyps; localized, regional, or distant colorectal cancer; and colorectal cancer–related death. Hyperplastic polyps also were included in the simulation.
“In order not to overestimate the efficacy of [narrow-band imaging],” the investigators used performance statistics derived from the literature and assumed an 84% rate of high-confidence classification of polyps, with a 94% sensitivity and an 89% specificity for identifying adenomas.
The model further assumed that a “resect and discard” policy was followed for all cases in which a high-confidence diagnosis was achieved using narrow-band imaging, and that all diminutive polyps in which a high-confidence diagnosis could not be made were removed and sent for formal histologic assessment.
The simulation first tested the cost-effectiveness of standard colonoscopy with pathology evaluations of all resected polyps in the cohort. The procedure was found to reduce colorectal cancer incidence by 75% and mortality by 79%.
When these outcomes were projected onto the U.S. population using 2009 census data and assuming a 23% rate of adherence to screening colonoscopy in the general population, standard colonoscopy screening was found to save $451 million annually, compared with no colonoscopy screening.
The simulation then tested the “resect and discard” approach and found an additional annual benefit of $25 per person screened. When this outcome was projected onto the U.S. population, this approach added an estimated $33 million in cost savings to the standard colonoscopy approach.
Importantly, the “resect and discard” approach showed no meaningful effect on the efficacy of colorectal cancer screening, Dr. Hassan and his colleagues noted.
“In theory, the 'resect and discard' strategy could affect the efficacy of colonoscopy screening. On one hand, the imperfect narrow-band imaging sensitivity for diminutive adenomas would misclassify some polyps as hyperplastic, preventing the standard follow-up strategy, whilst on the other, the misclassification of hyperplastic polyps as adenomatous lesions caused by the suboptimal specificity would lead to a more intensive and inappropriate 5-year colonoscopy surveillance in some individuals.
“However, the net effect of these two opposing forces was found to be meaningless, mainly because of the marginal efficacy associated with postpolypectomy surveillance, especially for diminutive lesions, compared with the substantial efficacy associated with polypectomy in preventing colorectal cancer,” they explained.
No industry funding supported this study. Dr. Hassan's colleagues reported ties to Medicsight, Viatronix, and Philips, as well as Olympus.